This invention relates to a reference-load variable hardness tester that permits measuring two different types of hardness, such as the Rockwell hardness and the Rockwell superficial hardness, by changing the reference-load to be applied on the specimen.
In general, the Rockwell hardness test is practiced with the reference-load of 10 kgf, and the Rockwell superficial hardness 3kgf. Some conventional hardness testers have allowed the shifting between such reference-loads by changing the position of the weight on the load application mechanism, or by means of the remote-controlled load application system.
Despite its structural simplicity, the hardness tester with the shiftable weight requires much skill in its weight-shifting operation. Meanwhile, the remote-load-control hardness tester is complex and, therefore, very costly.
The object of this invention is to solve such problems of the conventional hardness testers. The more particular object of this invention is to provide a hardness tester that permits changing the reference-load with high accuracy, by simple operation, and without rendering the tester mechanism complex.